System for establishing a plurality of fluid pressure levels



Jan 17, 1967 R. M. DOUGLAS SYSTEM FOR ESTABLIISIIING A PLURALITY OF FLUID PRESSURE LEVELS Filed June l5, 1964 ROBERT M. DOUGLAS INVENTOR.

BY m

ATTORNEY United States Patent() 3,298,386 SYSTEM FOR ESTABLISHING A PLURALITY OF FLUID PRESSURE LEVELS Robert M. Douglas, Dumont, NJ., assignor to Rexall Drug and Chemical Company, Los Angeles, Calif., a corporation of Delaware Filed .lune 15, 1964, Ser. No. 375,157 Claims. (Cl. 137-115) This invention relates to a novel system for establishing a plurality of fluid pressure levels and relates more specifically to a novel arrangement of differential pressure regulating means for establishing at least two, but preferably three pressure levels. The novel arrangement of the differential pressure regulators is particularly useful with hydraulic fluids which are employed to drive larger units such as single or double acting intensitiers, In high pressure technology, various -uses are made of intensiers of the foregoing type, although any pump that is driven by Ihydraulic fluid can be used in association with the novel system of this invention where the concept herein is applicable. y

In prior art systems where use is made of a hydraulic fluid to drive a low pressure piston face which acts on a smaller piston face to compress a fluid and discharge it into a high pressure process area, v-arious arrangements for creating and maintaining hydraulic fluid flows to the low pressure piston faces have been suggested and used. Such arrangements have included a differential pressure regulating valve in association with -other flow diverting systems such as compensators and/or pilot valves. In these arran-gements of the foregoing valve systems for diverting hydraulic fluids whi-le pressure levels of one type or another have been established, usually the excess ,energy in each of the pressure levels is not utilized since this is by-.passed to a reservoir and consequently such systems are inefiicient. It would be desirable to provide improvements in such-systems whereby a plural-ity of Ihydraulic fluid pressure levels could be established and the excess flow from the higher levels could be diverted to the next lower level, thus making efficient use of the energy contained therein.

It is an object of this invention to provide a novel arrangement of valve means for establishing a plurali-ty of hydraulic fluid pressure levels.

It is a further object of this invention to provide a novel arrangement of differential pressure regulating means for use in hydraulic actuated systems.

It is a still further object of this invention to provide a system for establishing at least two, but preferably three different hydraulic fluid pressure levels which can be used for driving hydraulic intensifier units.

This invention provides two differential pressure regulators embodying therein a resilient force and a piston, the said piston and resilient force being capable of act-uation by a hydraulic fluid supplied via inlet and outlet ports and conduits associated therewith for the establishment of a plurality of hydraulic fluid pressure levels.

The differential pressure regulators are arranged in such a manner, according to this invention, so that a first hydran-lic differential fluid p-ressure level can be established across an orifice in a conduit used for delivering hydraulic fluid at a pressure level to drive an intensifier system, for example, and flow in excess of that required for said first pressure level is by-passed to a second hydraulic fluid pressure level. In like manner, according t-o the invention, flow in excess of that required for maintaining the second pressure level is by-passed to a third level and arrangements can be provided for ultimately diverting to the sump any flow `in excess of that required for maintaining said third pressure level. As one skilled in this ice art will readily understand, work can 4be performed by the second and third hydraulic fluid pressure levels by proper diversion thereof to areas where they are needed.

In the ensuing description of this invention, it will be understood that the terms hydraulic fluid, fluid, oil or non-compressible fluid will be used synonymously. Piston orfspool valve with reference to the units in the differential pressure regulating valve are likewise intended to have a similar meaning, while a resilient force or resilient force constant are to be deemed equivalent to a spring force or spring force constant.

Reference is made to the attached drawing which represents the preferred arrangement of two differential pressure regulating valves and the manner in which they are associated for operation as note-d herein.

With brief reference to the drawing, numerals 1 and 31 represent enclosed cylindrical chambers which are adapted to contain therein a slidable piston or spool valve 2 and 32.. The spool valves as indicated slidably contact the surface of t-he chambers and move back and forth ther-ein according to certainv pressures acting thereon which will be indicated hereinafter. At one end of each of the valves 1 and 31 is located spring forces 3 and 33. These spring forces are usually of a fixed amount or force constant and abut the v-alve faces 4 and 34. l

Within the body of the chamber, spool spindles 5 and 35 form an integral unit with the other spool valve faces 6 and 36. It will be seen that chambers 7 and 37 are provided between the two spool valve faces for circulation of a hydraulic lluid such as an oil. At either end of Vthe cylindrical chambers 1 and 31 is located conduit ports 8 and 9 and 38 and 39 respectively. An inlet port 10 and corresponding inlet port 40 on chambers 1 and A31 are also provided for introduction of hydraulic fluid 4to chambers 7 and 37. Outlet ports 11 and 41 are likewise provided in chambers 1 and 31 respectively fordischarge -or by-pass of hydraulic fluid. Between the two cylindrical chambers, conduit 12 is provided and this conduit leads to conduit 13,4as well as conduit 14, check valve 15 an-d thence to conduits 16 and 17. i

Located within cylindrical chambers 1 and 31 are stops 18 and 18a, 19 and 19a, and 42 and 42a and 43 and 43a which function to limit the movement of the slidable spool valves so that they are not opening or closing the wrong port channels. Thus, in chamber 1, spool valve 2 moves to the right and abuts against stops 19 and 19a at which point inlet port 10 is opened. In its normal position, the spring force of spring 3 forces the spool valve 2 against the stops 18 and 18a to thereby close port 10. The spring and stops in chamber 31 function similarly. It will be noted that the springs 3 and 33 are located at opposite (effective) ends with respect to each other in the two differential pressure regulating valves.

The differential pressure regulating valves can be provided with a main conduit 60 for introduction of hydraulic fluid to actuate the spool valves in chambers 1 and 31 and thereby make it possible to establish a series of pressure levels.4 Hydraulic fluid is direc-ted through flow control valve 61 and onto conduit 62 where 4by virtue of pressure regulating valve or chamber 1, the pressure in line 60, Pla, is established relative to the hydraulic reference pressure level P1. In the `arrangem-ent illustrated in the drawing, fluid in excess of that required for maintaining said P1., pressure level is diver-ted from conduit 60 to conduit 63 and ythence to conduits 64 and 65.

As illustrated, conduit 62 can be tapped to provide conduit 66, which serves as a reference pilot pressure for at least one of the valves, as will be explained below. Constrictions 67 and 68 can be provided in conduits 69 and 70 which lead to ports S and 3S respectively. The operation of this novel system for establishing a plurality of pressure levels will now be described.

A hydraulic fluid is introduced as illustrated in the drawing through conduit 60, and a given percentage of the volume fiowing therethrough passes through flow control valve 61 to conduit 62 and on to establish a reference P1 pressure level. The flow in excess of that required for maintaining said first hydraulic fluid pressure level P1,L is diverted via conduits 63, 64 and 65. Por-t 10, which is normally kept closed by spool valve 2 will open, thus spilling into chamber 7 due to the fact that the fluid pressure from conduit 64 exerted on face 6 of the spool is greater than that of pressure level P1 and the spring force constant 3 which is exerted on the opposite face of the spool valve 4. When the fluid pressure level P1 plus the spring force constant 3 acting on spool valve face 4 exceeds the fluid pressure from conduit 64 acting on face 6, then the spool valve will slide to the left and close inlet port 10. The fluid pressures acting on the spool valve faces can also come to a dynamic balance and continuously throttle the hydraulic iiuid.

By-passed fluid from chamber 7 iiows to conduit 12 through outlet port 11 and thence to conduits 13 and 14, through check valve 15 and conduits 16 and 17. In this arrangement, valve 31 acts opposite with respect t-o valve 1, that is, the valve is normally open rather than closed and the spring force constant is located at the opposite end with respect to `that of valve 1. In this case, when the pressure of the iiuid in line 17 plus the force of spring 33 acting on face 34 is less than the P1 pressure level acting through conduit 7), the spool valve 32 will move to the left to close inlet port 40. When the pressure level P1 acting through conduit 70 on spool valve face 36 becomes less than the spring force 33 and the Huid.

It will be noted from the foregoing that in the absence Y of any Huid pressures, the valves 1 and 31 are normally closed and normally open respectively. The dynamic balance of the spool valves in each case is determined Eby the sum of forces acting on its faces so that in this manner, in addition to the first fluid pressure level P12, fluid pressure levels P2 and P3 can 'be established as described below. Thus, fiuid pressure level P2 is established by diverting flow from conduit 12 to conduit 13 when valve 31 is closed. This pressure level P2 is always maintained below the P1 pressure level (which is controlled lby the downstream process side) by at least the spring force constant in force per unit area of spring 33. It can be seen, therefore, that it is the arrangement of the valves and the valueof the spring force constant 33 which establishes this difference in the two fluid pressures P1 and P2. The P3 pressure level can be established by the outlet fiow of valve 31 through port 41 and conduit 41a. A relief valve 4117 can be provided in association with this conduit to establish the P3 uid pressure level. A particular use for these differential pressure regulating valves as arranged and illustratedv in the attached drawing is disclosed in cto-pending application Serial Number 372,266, filed June 3, 1964 now Patent No. 3,234,882 for use in driving two single acting intensifiers in a pipless method.

From the above description ofthe preferred arrangement of the differential pressure regulating valves, it will be seen that the reference pressure level P1 which can fbe used to drive a piston, for example, is also used in this case as the pilot or reference pressure for actuation of spool valves 2 and 32, while the P12 and P2 are the pressures being controlled. I-t can also 'be seen that in this preferred arrangement of thevalves, the flow in excess of that required to maintain the fluid pressure level P1a is by-passed and is used to establish a second uid pressure level P2 via the valve arrangements herein and flow in excess of that required to maintain said second fluid pressure level P2 is further by-passed via the second valve and used to establish a third fluid pressure'level P3 as described hereinabove and illustrated in the drawing.

Although it is indicated above that one use for the novel arrangement of the valves herein is in driving a hydraulic intensifier, other uses for such an arrangement include the driving of various other units requiring a plurality of driving forces as will be understood by those skilled in this art.

While the foregoing represents a preferred embodiment and arrangement of the pressure differential regulating valves of this invention, resort can be had to innovations and changes which fall within the scope of the invention and the coverage of the appended claims.

What is claimed is:

1. In combination, a first and second differential pressure regulating valve, each of said valves comprising an enclosed cylindrical chamber, a slidable spool valve therein, a fixed resilient force opposing one end of said spool and abutting on one end of said chamber in said first valve, a given resilient force opposing the opposite end of the spool in the second chamber with respect to the spool in the first chamber and abutting on said opposite end of said second chamber, a conduit in each of said chambers for providing =a reference fiuid pressure for actuation of said spool valves against at least the fixed resilient forces therein, said first valve being provided with an inlet and an outlet port, said inlet port being maintained in a normally closed position by the spool valve in association with the given resilient force, said second valve being provided with an inlet and an outlet port, said inlet por-t being maintained in a normally open position yby the spool valve in association with the given resilient force and conduit connections between the outlet port of said first valve and the inlet port of said second valve.

2. The combination of the differential pressure regulating valves of claim 1 wherein a check valve is provided in the conduit connection between 4said rst valve outlet y port and the. inlet port of said second valve.

. Sure regulating valve, ,each of said valves comprising an enclosed cylindrical chamber, a spool valve for movement in slidable contact'in said chamber, a fixed spring force constant opposing one end of said spool and abutting on one end of said chamber in said first valve, a xed spring force constant opposing the opposite end of the spool in the second chamber with respect to the spool in the first chamber and abutting on said opposite end of the secon-d chamber, a conduit in each of said chambers for providing a reference uid pressure for actuation of said spool valves,.a conduit in the opposite end of each chamber for providing a fiuid pressure which is to be controlled, said first valve being provided with an inlet and an outlet port, said inlet port being maintained .in a normally closed position Iby the spool in association with the given spring force, said second valve being provided with an inlet and an outlet port, said inlet port b'eing maintained in a normally open position by the spool in association with the given spring force, and conduit connections between the outlet port of `said first valve and the inlet port of said second valve.

5. The combination of the pressure regulating valves of claim 4 wherein the conduit connection between the outlet port of said first valve is associated with the conduit of the second chamber for providing a uid pressure which is additive to that of the spring force for actuation of the spool valve in said second chamber.

No references cited.

WILLIAM F. ODEA, Primary Examiner.

D. DONOVAN, Assistant Examiner. 

1. IN COMBINATION, A FIRST AND SECOND DIFFERENTIAL PRESSURE REGULATING VALVE, EACH OF SAID VALVES COMPRISING AN ENCLOSED CYLINDRICAL CHAMBER, A SLIDABLE SPOOL VALVE THEREIN, A FIXED RESILIENT FORCE OPPOSING ONE END OF SAID SPOOL AND ABUTTING ON ONE END OF SAID CHAMBER IN SAID FIRST VALVE, A GIVEN RESILIENT FORCE OPPOSING THE OPPOSITE END OF THE SPOOL IN THE SECOND CHAMBER WITH RESPECT TO THE SPOOL IN THE FIRST CHAMBER AND ABUTTING ON SAID OPPOSITE END OF SAID SECOND CHAMBER, A CONDUIT IN EACH OF SAID CHAMBERS FOR PROVIDING A REFERENCE FLUID PRESSURE FOR ACTUATION OF SAID SPOOL VALVES AGAINST AT LEAST THE FIXED RESILIENT FORCES THEREIN, SAID FIRST VALVE BEING PROVIDED WITH AN INLET AND AN OUTLET PORT, SAID INLET PORT BEING MAINTAINED IN A NORMALLY CLOSED POSITION BY THE SPOOL VALVE IN ASSOCIATION WITH THE GIVEN RESILIENT FORCE, SAID SECOND VALVE BEING PROVIDED WITH AN INLET AND AN OUTLET PORT, SAID INLET PORT BEING MAINTAINED IN A NORMALLY OPEN POSITION BY THE SPOOL VALVE IN ASSOCIATION WITH THE GIVEN RESILIENT FORCE AND CONDUIT CONNECTIONS BETWEEN THE OUTLET PORT OF SAID FIRST VALVE AND THE INLET PORT OF SAID SECOND VALVE. 